Projector cooldown

Dear Lazyweb,

Why when I turn my projector off, does the fan spin up for a few minutes? My first thought was that it doesn't make sense, because it's not getting any hotter what with the power being off. Furthermore, cooling it off fast will only heat-cycle it harder. On the other hand, maybe the filliment is soft; maybe this is protecting it from the once in a blue moon that I'll move the thing right after watching? My only other thought is that there is some component that would get hotter before it got cooler if the fan didn't stay on, but that (a) sounds bogus and (b) seems like a design way too close to the edge and (c) doesn't explain why the fan would have to spin faster for cool-down thanfor steady-state projecting.